"The Quena"

The quena or kena, traditional flute of the Andes, is about the easiest non-trivial instrument you could make. It's just a tube with seven finger holes and a notch to blow against; but, oh what a sound! Why would you want to make one? Because you like the sound. Because you always wanted to make an instrument but didn't know where to start. Because you just need to play that heavenly Andean music. Note that quena making is not a science. This method does not guarantee an excellent instrument. There is no standard. Precision is not a requirement. But if you make one, you can make more, and improve each new one.
                                   Materials
You can make a quena out of any kind of tube: bamboo, wood, metal, plastic, clay. The material has only a little effect on the sound of the instrument. The inside diameter should be 1.75cm (11/16") plus or minus 0.15cm (1/16"), and the wall should not be too thick (3/32 to 5/32"). The wall should be straight; either cylindrical or very slightly conical (tapered, widest end at the mouth). The most readily available plastic tubing and the most easily worked is the PVC water pipe from your local hardware or home improvement store. There are two kinds of PVC pipe: cold water (irrigation) and hot water (180 deg.). (In the store they are identified by "schedule number", but I don't remember what those are.) The 180 deg pipe has thinner walls, and it's PVC is (supposedly) less toxic. The inside diameter of the 180 deg. pipe is nominally 3/4", but in fact is less (11/16"). The irrigation pipe (73 deg., schedule 40) is in fact 3/4" in diam. I have made quenas of both using the same hole positions. The irrigation pipe works OK as a "quena en MI" (that's how my Bolivian friends call the standard quena whose lowest tone is G, MI being the relative minor of G), but is more suitable for a quena en re (useful for Ecuadorian music) or for a quenacho (en SI). Did I say "less toxic"? Yes. There is mounting evidence that polyvinyl chloride (one of the components of PVC plastic) and other organochlorides (including DDT and PCBs) in our environment contribute to development of cancers (see Mother Jones MJ94).    
                                Procedure
Cut the tube to length (the dimension marked "end" in the tables). I always cut the tube a little long and then trim it to pitch after I've made the notch. Form the notch: Use a sandpaper-covered dowel, a round bastard file (or rasp), or a hot iron. The diameter of the tool should be equal to or slightly smaller than the width of the notch. The trick to making a well-rounded, U-shaped notch is to hold the tool perpendicular to the body of the quena. If the tool is a file, you can only use very short stokes, as the end of the file hits the opposite wall of the tube. The cylindrical shape of the tool ensures that the end of the notch remains semicircular. It doesn't take much deepening of the notch to raise the pitch a lot. Filing perpendicularly dulls the edge that you blow on, so you have to sharpen it again. This time use a dowel or file larger than the notch's width, and use diagonal strokes on both sides of the blow-edge. Don't oversharpen lest you make a pointy notch (that is, a V-shape instead of the desired U-shape). The goal at this stage is to bevel the edges of the notch that you've already made, not to make the notch bigger. Bevel the edges of the notch-cut from both the inside and the outside of the tube. The proportion of inside to outside filing is a matter of taste. Most people place the blowing edge at the middle of the tube wall; but I have a kena with the edge at the inside of the tube wall (they filed only on the outside). In any case you have to adjust your lips to blow at the edge you have formed. Draw a straight line from the bottom of the notch down to the foot of the quena. This will serve as a guide for positioning the finger holes. Use a length of adhesive tape to help make the line straight. Mark the positions of the finger holes. Traditionally, the holes are in a straight line; but you may find the instrument easier to play if you offset some of the holes to one side or the other to match the lengths of your fingers. Perforate the tube. If you use a hot iron to perforate, be sure not to breathe the fumes, especially not those of a plastic tube. Arrange a work space outdoors in such a way that the breeze carries the fumes away from you. If you are using a power drill, make pilot holes with a small drill bit. Then follow with bits progressively larger in diameter. You now have a quena which probably plays, but plays out of tune, and is generally low in pitch (flat). Go to the section on tuning.
                                     Tools
Tube cutter. The tool for cutting copper pipe -- the kind that you screw down tighter and tighter as you rotate it around the tube -- works well on bamboo and PVC, too, though you have to carefully steer it through the first few revolutions to ensure that it doesn't start spiraling. A hacksaw also works for plastic. It makes a mess of bamboo. A knife is the traditional cutting tool for bamboo. Perforator. Hot metal rod. You can use rebar, railroad spikes, soldering pencil, whatever. Your work will be easier and neater if you have several irons of sizes to match the holes you need to make. Sharpen the business end a little so the iron will enter where you point it. You can heat the iron in the embers of a bonfire or barbecue. Drill. A power drill can easily split bamboo; the hot iron is best. Round files. Several round or half-round bastard files. Or sandpaper wrapped around a rod, dowel, or tube. The latter is not very useful for the notch. Reamer. The deburrer that comes with the tube cutter works well for keeping the holes round after you enlarge them with a file or hot metal rod. Sandpaper. Fine wet-or-dry sandpaper (for finishing). Tape measure. For transferring dimensions to your tube. Tuning standard. Some device that generates sustained tones at any pitch is best. I use an electronic Korg chromatic tuner. You can also rest a weight on a key of an electronic organ to sustain a tone while your hands are busy playing the quena. If you use an acoustic piano, be sure that the piano is tuned to standard pitch. All stringed instruments go flat (lower in pitch) with age.